question about hooking up controls to multiple systems

[BurgerKingDiamond]

    I want to put my ps2 in my cabinet along with my PC so I can play Gradius V and Raiden III and a few other suitable arcade games (perhaps my 360 too for some Mushihimesama action..) . Right now I have my controls connected to my PC through a cthulhu board, which is similar to an ipac.

    What I want to do is connect all my grounds from the joystick and buttons to a grounding point, and then from there run one wire to the ground of the cthulhu and another wire to the ground of the hacked ps2 pad. Then for each button I just run two wires from the NO lead, one each to the corresponding lead on the cthulhu and ps2 controller.

This way I won't need to have a switch or anything. It will automatically work for whatever system is turned on at the time. Is there any reason why this won't work, or is a bad idea? I don't know much about electronics. Is it ok that the cthulhu and ps2 both share the same ground? That's the only thing I could see not working... If so I could just put a switch to have one or the other grounded to the joystick/buttons at a time.

Thanks for reading.
BKD

[SavannahLion]

Point 1: Do you intend to have both powered at the same time? That might make a difference. Which leads me right into point #2

Point 2: If you have them both powered, that might cause problems. The cthulhu board is USB based, no? Then it runs off of +5v give or take half a volt. The PS2 controllers operate somewhere between 5v-3.3v for the VCC and 9v-7.9v for the motor (depending on what reference source you use). I don't know how either controller will respond to a voltage disparity but I would guess the USB fuses would trip if they go above a certain voltage. Heck, I don't even know if the controller will send that kind of voltage up the USB lines if it gets that voltage from the other side.

Point 3: I haven't taken apart a PS2 controller so I'm just going on a possible caveat emptor on other controllers. Depending on how the PS2 circuit is laid out, it's possible that the buttons aren't true +5v->0v kind of thing arcades typically use. For example, one PC controller I tore apart had no way to tap directly into the IC (like I wanted) since, as near as I can figure, some of the buttons were a +5v->0v arrangement, while two appeared to be a pulsed AC signal (with diodes naturally) so when the IC pulled the signal up to +5v on button A, it would see if it was pulled to 0. Then it would flip the polarity for button B and see if that was pulled down to 0v. And still haven't quite worked out how two other buttons functioned. Point being, if the controller is doing some weird ---steaming pile of meadow muffin--- with its buttons, you're going to get weird ---steaming pile of meadow muffin--- if you try to cross wire them with another controller. You can get an idea of what's going on if you trace each button back to the IC and make sure there's a 1-1 relationship for each pin (less ground pin). If there is, it's worth a shot. If there's not (like two buttons to one pin) then you can try but don't expect anything. From a discussion I read about the 360 controllers, they like to do weird ---steaming pile of meadow muffin--- with their buttons. But I could be wrong about that, I never took one of those apart either.

I say... try your original idea and see if it works. Make sure you can pull the wiring and retry a different scheme though. IOW, attach really really long leads to the PS2 pads then hot glue the suckers down that way you're not stuck unsoldering/resoldering five or six times. I would start by following the tutorials on hacking PS2 pads to arcade controllers. Then test the set up without the Cthulu board. That way you know it at least that setup works and you're not left trying to figure out what's wrong and looking in the wrong places.

If your idea fails, just rewire to a new idea.

[BurgerKingDiamond]

thanks for the lengthy reply SavannahLion. To answer your question, I only plan on having either the PC or the PS2 turned on at a time. I think I'll just put a switch on there in case I they accidentally both get turned on at once. Who knows what would happen, but I'll try and avoid the headache of finding out.

[northerngames]

I had my ipac dc pc & ps on DB-25 switchbox's that way there is no extra current going anywhere it should not be.

[BurgerKingDiamond]

If I use one of those switch boxes can I just switch on/off the ground so that I just have the particular controller that I want to use grounded to the joystick/buttons? Then the others will be off right?

[northerngames]

right.

I wired my cp buttons joys etc. to the DB-25's input all joys button etc share the common ground.

then ipac ps and dreamcast go to each of the DB-25's output channels.

setting A ipac pc controls

setting B dreamcast

setting C playstation

etc.

just make sure you use a controller hack that use's a common ground for each console.

if your going analog that is a whole nother story though.

it is a decent amount of work wiring them all up like that but once the CP is done and ran to the DB box you have an option to connect any system to the controls without having to tamper with any of control panel parts or the wiring again.

you just wire the console controllers from the console to the DB-25 outputs so if you mess anything up it is only on the console half and not the Cp anymore plus it is nice to be able to just flick a switch and be ready to go on to the next gaming device.

also if something does act up you just unplug it and fix it instead on that particular console instead or rewiring the cp or figuring out what console wire went goofy when there is a ton of wiring all over the place.

if you just have one thing running it defeats the purpose but if you want multiple system's that can switch pretty much on the fly then the DB box's are a must.

there may be something out there better but I did all mine DB-25 and everything was great and it also keep's the cab looking neat and clean inside if you ziptie your wire harness's instead of havfing tangled wire's mixed between a few console's as that can get messy fast if there is ever a problem.   

[BurgerKingDiamond]

SWEET. This sounds like exactly what I need. I'll post an update when it's finished (might be a little while). 

[opt2not]

I had my ipac dc pc & ps on DB-25 switchbox's that way there is no extra current going anywhere it should not be.

+1

This is a great set-up. Just make sure you keep track of what connects to each DB-25 pin, and you'll be good. This makes it pretty easy to set-up multiple systems down the line as well!

[BurgerKingDiamond]

My setup is gonna be supreme. More shoot-em-ups than I'll have time to play.